The present invention relates to a blow-molded bottle useful as a container for food such as soy or salad oil, for alcoholic beverage and soft drink, for detergents, for organic solvents such as benzene, toluene or xylene, or for oil such as gasoline, kerosine, light oil or heavy oil. Particularly, it relates to a multi-layered blow-molded bottle which is excellent in gas-barrier property, stiffness and impact resistance, exhibits a high interlaminar peel strength and satisfies the severe physical requirements necessitated for the use as a large-scale blow-molded bottle such as an automotive gasoline tank.
Up to this time, a polyolefin resin has been generally used as a material for a blow-molded bottle. However, a polyolefin resin is disadvantageously poor in gas-barrier property and solvent resistance, though it is inexpensive and excellent in water resistance and heat sealability.
Accordingly, it has been attempted to laminate a polyolefin resin with various materials for the purpose of improving the various performance such as gas-barrier property and solvent resistance. For example, Japanese Patent Publication No. 49989/1980 (corresponding to British Patent No. 1335791) discloses a process for the production of a multi-layered blow-molded bottle which comprises laminating a layer of a crystalline polyolefin with a layer of a modified crystalline polyolefin having an unsaturated polycarboxylic acid and an anhydride group thereof grafted thereto and a layer of nylon.
Further, multi-layered bottles produced by laminating polyolefin with polyamide by the use of an olefin resin modified with an unsaturated carboxylic acid or an anhydride thereof such as maleic anhydride as an adhesive and various processes for the production thereof have been proposed.
Such bottles and processes are disclosed in, for example, Japanese Patent Laid-Open Nos. 86579/1975, 96878/1976, 125463/1976 (corresponding to British Patent No. 1527611), 150468/1976, 45465/1977, 62574/1977, 21676/1978, 23774/1978, 113678/1979, 91634/1980, 106857/1981, 120345/1981, 11046/1982, 42745/1982 and 125044/1982.
However, the multi-layered bottles of the prior art do not exhibit high adhesion enough to withstand the environmental conditions severer than those of ordinary uses.
Particularly, the environmental conditions of a large-scale fuel container necessitating high impact resistance and adhesion, such as a gasoline tank, are much severer than those of ordinary uses, so that an improvement in the adhesion has been eagerly demanded
An object of the present invention resides in improving the adhesion of a polyolefin layer to a barrier layer made of a polyamide resin or the like, in which the multi-layered blow-molded bottles according to the prior art are poor.
Another object of the present invention resides in providing a multi-layered blow-molded bottle which is excellent in various characteristics such as moldability, environmental stress-crack resistance (ESCR) and impact resistance.